Israel's bombardment of the Gaza Strip continued late into the night on Friday, with reports of sustained air strikes and ground attacks.
A strike on the Nuseirat refugee camp in central Gaza killed at least 18 people, according to Palestinian media.
People in another camp, Bureij, were ordered by Israel's army to move south as it continued its ground offensive.
In New York, the UN Security Council adopted a resolution urging more humanitarian aid for Gaza.
However the motion fell short of calling for an immediate ceasefire in the war.
Wafa, the official Palestinian news agency, said at least 18 people died and dozens were injured in an air strike on a house in Nuseirat, in central Gaza.
An air strike also destroyed a water treatment plant in Jabalia, northern Gaza, it added.
Residents of Bureij, which is close to Nuseirat, were ordered to "leave immediately for their own security" and move south towards the city of Deir al-Balah.
"Where should we go to?" Ziad, a medic and father of six, told Reuters news agency by phone. "There is no safe place."
Another displaced person, wheelchair user Walaa al-Medini, said she had been injured in a strike on her home in Gaza City.